AddonScriptorDE: I was able to get those Akamai SecureHD streams working with help with KSV. He pointed me in the right direction for the token generation. Also that large data64 block is really a swf file encoded in the meta-data of the FLV file. It contains the action script that generates the tokens that KSV showed me how to generate.
It works by just downloading the file locally and having xbmc play it as it downloads. It uses flvlib to read the onEdge blocks and sends the proper command to the server. I am just going to put together a script module that one can feed the stream url and swf url so it will start the stream playing in XBMC for you.
I was hoping for something better then saving the file locally but I couldn't work out a good way to feed it to XBMC Player.
Let me know if you are interested in trying what I have currently.
Edit:
I am actually making a modified version of XBMCLocalProxy from
http://forum.xbmc.org/showthread.php?tid=95369
You basically base64 encode the video url of the stream and the url of the swf player to be used as parameters for the local proxy. The local proxy will then serve video to XBMC and handled all the tokens, signing and hashes for you.
It has to jump through a few hoops to get everything going. When XBMC connects we have to start the flv download to get the first onEdge dictionary. It uses the session and streamname values in the onEdge dictionary. It downloads the swf player to calculate an MD5 of the decompressed player. It will decompress the swf for you if it isn't already. That MD5 is appended to the sessionID. That string is then hmac sha1 signed and that digest is encoded to base64. This base64 balue is the x-Akamai-Streaming-SessionToken header value. It then sends the sendNewToken command to the correct streamname. The flv data is passed on to XBMC for playback. It will then continue to play and not drop after a short time.
Hopefully this will make it easier to use these streams with XBMC in the future.
I still need to work out a couple problems with content length being sent so XBMC doesn't think it is buffering a 2GB file. I also need to work on it properly shutting down the proxy server.